The plantar fascia is a ligament structure that attaches between the calcaneous bone of the heel and the metatarsals located in the front part of the human foot. In particular, the plantar fascia maintains the arch of the foot and is placed in tension during walking and running.
Traumatic or, more typically, chronic overstressing of the plantar fascia leads to a condition commonly referred to as “plantar fasciitis”. This condition is characterized by inflammation, as well as tearing and shortening of the plantar fascia through scarring. The inflammation and tearing usually occur at the point where the fascia is attached to the heel bone and can cause the growth of spike-like projections of new bone, called heel spurs.
The plantar fasciitis condition causes mild to severe pain in the heel or arch which, if left untreated, can interfere with walking and daily living activities, as well as athletic activity. This condition can afflict both athletic and sedentary persons, and is especially common in the obese and in people who exercise on hard surfaces.
The symptoms of plantar fasciitis usually occur in the morning, resulting from activity of the previous day, due to cramping and muscle tightening of the foot and leg at night while the individual is asleep. A broad range of treatments are prescribed for plantar fasciitis, depending upon the severity of the injury and length of time the condition has existed. Among commonly used treatments are rest, ice, anti-inflammatory/analgesia medication, ultrasound to decrease inflammatory response, taping, heel pads, support socks, orthopedic device, physical therapy and even surgery. The various orthosis, (e.g. device or support, especially for the foot, used to relieve or correct an orthopedic problem), include walking type splints, shoe insole inserts and night splints.
Although similar in appearance to foot and ankle casts, also called walking casts, a night splint for the treatment of plantar fasciitis is only superficially similar to a walking cast. A foot or ankle cast is made so that the force vector of the patient's weight passes vertically through the cast and the patient's leg when he is standing. In the medical industry, no walking casts are made which do not place the bottom of the patient's foot at a 90 degree angle to the patients leg, which is consistent with a vertical force vector. Thus, no walking casts are built to induce and maintain dorsiflexion or plantar flexion. In addition, a walking cast is made to provide the patient with a weight-bearing region forward of the heel, on which the weight of the body is placed when walking, and from which the patient can pivot forward when taking the next stride. The bearing and pivoting structure can be a rounded knob under the mid region of the foot, or it can be a rounded surface which covers the bottom of the cast from heel to toe. A walking cast may also have a cushioning region directly under the heel to absorb some of the shock of walking. Walking casts are not made to wear in bed at night, and are not made to induce a stretching effect on tendons. They are made to provide support to healing ankle and foot joints and bones, and to control the motion of these healing joints and bones while healing takes place.
To treat plantar fasciitis, it is necessary to use considerable force to counteract the strong muscles and tendons of the lower leg and foot. If this force is applied improperly, pressure points can result, with resulting discomfort and complications for some patients. Some patients have reduced blood circulation or sensation in the feet, such as patients with diabetes, vascular insufficiency, polio, stroke, trauma, or neurological problems. In such patients, if they need to use a night splint for treatment of plantar fasciitis, it is important to minimize the pressure points exerted by the night splint on the patient's foot, while still exerting the necessary force on the foot and lower leg structure. The night splint must also not bruise or scratch the collateral leg during sleep, must not soil or tear bedding, and must be compatible with a sleeping partner. Walking casts are not designed to accomplish these objects.
In contrast, night splints allow for rehabilitation of the plantar fascia by maintaining the foot in a dorsiflexed condition such that the plantar fascia is slightly extended and not allowed to contract during the night. Conventional night splints consist, essentially, of a boot-like structure which is strapped to a patent's lower leg and foot. Although more streamlined than walking splints, boot-like splints are still quite heavy and bulky and, as such, are uncomfortable and interfere with sleep. For example, the boot splint impedes the wearer's ease of moving between sleep positions. Moreover, the bulk of the splint may bruise or scratch the collateral leg during sleep, and may interfere with a sleeping spouse. Further, such splints encompass the ankle region of a person, and may exert pressure points on the patient's foot or lower leg structure. Such pressure point concerns are even more critical for patient's having reduced blood circulation or sensation in the feet, such as patients with diabetes, vascular insufficiency, polio, stroke, trauma, or neurological problems.
Another type of conventional night splint is a generally L-shaped brace. The top portion of the L-shaped brace is configured to fit around the rear and sides of the patient's calf, ankle and heel, while the bottom portion of the L-shaped brace extends forwardly beneath the sole of the foot. These braces are held to the foot and leg by strapping, or the like. While such splints are less bulky than boot-type splints, some patients still complain that these splints are uncomfortable, particularly when worn in bed. The rigid portion of the splint is disposed between the patient and the bed mattress in most positions and, hence, can cause pressure points at the rear and side of the heel, ankle, and lower leg.
Another type of device for maintaining a dorsiflexion of the plantar fascia ligament is described in U.S. Pat. No. 5,399,155 issued to Strassburg et al. The device consists of an over-the-calf sock, a d-ring attached to the front (shin) side, and an adjustable support strap attached to the toe portion of the sock. The support strap is passed through the d-ring loop, and secures to itself utilizing hook and loop attachment. The degree of stretch provided to the to plantar fascia ligament can be controlled by adjusting the tension provided by the support strap. Such devices do not provide any lateral support for the foot. Furthermore, tension in the support strap tends to pull the sock down the leg of the wearer, which allows the foot to relax to plantarflexed position.
Accordingly, what is needed is a night splint for the rehabilitation of plantar fasciitis that is comfortable to wear during sleeping, while maintaining the plantar fascia in a slight stretch. Further needed is for the night splint to be light weight, streamline, and have a low profile, in order to enhance comfort to the wearer.